Silphenylene compound and process for producing the same

ABSTRACT

The present invention relates to a silphenylene compound represented by the following formula (1): 
     
       
         
         
             
             
         
       
     
     in which R1 to R4 each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and R5 and R6 each independently represents a divalent hydrocarbon group having 2 to 8 carbon atoms. The silphenylene compound of the present invention is useful as a flexible printed wiring board material, a passivation film for IC chips, and a panel material for liquid crystals.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on Japanese patent application No. 2007-323032filed on Dec. 14, 2007, the entire contents thereof being herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a novel silphenylene compound. Morespecifically, it relates to a novel silphenylene compound useful as amodifier for polyimide resins, polyamide resins, epoxy resins, and thelike and to a process for producing the compound.

BACKGROUND OF THE INVENTION

Polyimide resins and the like are known as resins having heatresistance, burning resistance, electrical and mechanical properties,and the like and have been widely used as composite materials forcopper-plate laminate sheets and multilayer printed wiring boardmaterials. Polyimide resins have also been utilized as passivation filmsfor multilayer wiring of LSI, α-ray shielding films for memory elements,multilayer wiring insulating films such as magnetic heads, and varnishesfor liquid crystal orientation films and the like and also as films forflexible printed wiring boards and the like.

However, the polyimide resins lack self-adhesiveness to metals such assilicon and copper and inorganic materials such as glass and solubilitythereof is limited only to high boiling polar solvents as well asviscosity as varnish is high and cured products thereof show highmelting points, so that the resins have such disadvantages that theylack moldability and processability. Therefore, it is desired to modifythem so as to be applicable to more diversified uses.

Conventionally, as silicon-based compounds having a succinic anhydridemoiety, there are known succinic anhydride-modified silicones obtainedby subjecting an organohydrogenpolysiloxane and a succinic anhydridehaving an unsaturated group to an addition reaction throughhydrosilylation (Patent Documents 1 and 2).

Patent Document 1: JP-A-61-157531

Patent Document 2: JP-A-5-331291

SUMMARY OF THE INVENTION

An object of the invention is to provide a novel silphenylene compoundin which a succinic anhydride derivative is added to a silane compoundand a process for producing the same.

As a result of extensive studies for achieving the above object, thepresent inventors have found a silphenylene compound represented by thefollowing formula (1) and a process for producing the same.

Namely, the present invention provides the following items 1 to 6.

1. A silphenylene compound represented by the following formula (1):

wherein R1 to R4 each independently represents a hydrogen atom or amonovalent hydrocarbon group having 1 to 6 carbon atoms, and R5 and R6each independently represents a divalent hydrocarbon group having 2 to 8carbon atoms.

2. The silphenylene compound according to item 1 above, wherein R1 to R4each represents a methyl group.

3. The silphenylene compound according to item 1 above, wherein R5 andR6 each independently represents an ethylene group or an n-propylenegroup.

4. A process for producing the silphenylene compound according to item 1above, which comprises subjecting to an addition reaction a silanecompound represented by the following formula (2):

wherein R1 to R4 each independently represents a hydrogen atom or amonovalent hydrocarbon group having 1 to 6 carbon atoms, and

a succinic anhydride represented by the following formula (3):

wherein R7 represents a monovalent hydrocarbon group having 2 to 8carbon atoms and containing an unsaturated group.

5. A polyimide resin produced by using the silphenylene compoundaccording to item 1 above as a monomer.

6. The polyimide resin according to item 5 above, which is producedthrough a process using an addition reaction or a polycondensationreaction.

When the novel silphenylene compound of the invention is used inpolyimides, polyamides, epoxy resins, or the like, it contributes to animprovement in adhesiveness to substrates, heat resistance, andmechanical strength. Therefore, it is useful as a flexible printedwiring board material, a passivation film for IC chips, and a panelmaterial for liquid crystals. Since the novel silphenylene compound ofthe invention has structurally a silphenylene skeleton, it is consideredto be excellent in terms of heat resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ¹H-NMR chart of the silphenylene compound of Example 1.

FIG. 2 is a ¹H-NMR chart of the silphenylene-containing polyimide resinof Example 2.

DETAILED DESCRIPTION OF THE INVENTION

The novel silphenylene compound of the invention is represented by thefollowing formula (1):

In the formula (1), R1 to R4 each independently represents a hydrogenatom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. Assuch a monovalent hydrocarbon group, there may be mentioned alkyl groupssuch as a methyl group, an ethyl group, a propyl group, an isopropylgroup, a butyl group, an isobutyl group, an octyl group, and acyclohexyl group; and aryl groups such as a phenyl group, a tolyl group,and a naphthyl group. Of these, a methyl group is preferred in view ofavailability of raw materials.

In the formula (1), R5 and R6 each independently represents a divalenthydrocarbon group having 2 to 8 carbon atoms. As such a divalenthydrocarbon group, there may be mentioned an ethylene group, ann-propylene group, an iso-propylene group, an n-butylene group, ann-octylene group, a pentylene group, a hexylene group, and the like. Ofthese, an ethylene group or an n-propylene group is preferred in view ofeconomical efficiency.

The production process of the invention is a process for obtaining theabove silphenylene compound by subjecting a silane compound representedby the following formula (2) and a succinic anhydride derivativerepresented by the following formula (3) to an addition reaction throughhydrosilylation:

In the formula (2), R1 to R4 are the same as defined in the formula (1)and each independently represents a hydrogen atom or a monovalenthydrocarbon group having 1 to 6 carbon atoms. As specific examples ofthe silane compound (2), there may be mentioned1,4-bis(dimethylsilyl)benzene, 1,4-bis(diethylsilyl)benzene,1,4-bis(diphenylsilyl)benzene, 1,4-bis(methylphenylsilyl)benzene, andthe like.

In the formula (3), R7 represents a monovalent hydrocarbon group having2 to 8 carbon atoms and containing an unsaturated group. As such ahydrocarbon group, there may be mentioned a vinyl group, an allyl group,a hexenyl group, an octenyl group, an acryloylpropyl group, anacryloylmethyl group, a methacryloylpropyl group, a cyclohexenylethylgroup, and the like. Of these, a vinyl group or an allyl group ispreferred in view of economical efficiency. In this connection, R7corresponds each of R5 and R6 in the formula (1). As specific examplesof the compound represented by the formula (3), there may be mentionedallylsuccinic anhydride, vinylsuccinic anhydride, and the like.

The catalyst to be used in the hydrosilylation reaction may be acatalyst hitherto known and, for example, a platinum-based catalyst suchas platinum carbon, chloroplatinic acid, an alcohol solution ofchloroplatinum acid, an olefin complex of platinum, an alkenylsiloxanecomplex of platinum, a carbonyl complex of platinum; a rhodium-basedcatalyst such as tris(triphenylphosphine)rhodium; an iridium-basedcatalyst such as bis(cyclooctadienyl)dichloroiridium is suitably used.The amount of the above-mentioned catalyst for the addition reaction tobe used may be an effective amount as a catalyst and is not particularlylimited but is usually about 0.0001 to 20 parts by weight, preferablyabout 0.001 to 5 parts by weight based on 100 parts by weight of thetotal amount of the above-mentioned silane compound and succinicanhydride derivative.

The above-mentioned addition reaction proceeds without using any solventbut the reaction can be carried out under milder conditions with using asolvent. As the solvent, there may be mentioned aromatic hydrocarbonsolvents such as toluene and xylene, aliphatic hydrocarbon solvents suchas hexane and octane, ethereal solvents such as tetrahydrofuran anddioxane, and the like. They may be used singly or as a combination oftwo or more thereof. The reaction temperature is 20° C. to 150° C.,preferably 50° C. to 120° C. and the reaction time may be about 1 hourto 24 hours. The amount of the succinic anhydride derivative to be usedmay be 1.0 to 1.2 mol with respect to 1 mol of the Si—H group in thesilane compound.

The thus-obtained silphenylene compound of the invention is useful as amodifier for resins such as polyimide resins, polyamide resins, andepoxy resins. When these resins are produced by using the silphenylenecompound of the invention as a monomer, heat resistance is particularlyimproved. In this connection, the content of the silphenylene compoundof the invention in the above resin is preferably 5 to 80% by weight.

As the process for producing various resins using the silphenylenecompound of the invention as a monomer, a variety of processes may bementioned and, for example, processes using an addition reaction, apolycondensation reaction, and the like may be mentioned.

EXAMPLES Example 1 Synthesis of Silphenylene Compound

Into a 500 ml flask fitted with a stirrer, a thermometer, and acondenser were charged 101.6 g (0.726 mol) of allylsuccinic anhydride, 1g of a 2% ethanol solution of chloroplatinic acid, and 150 g of toluene,followed by heating on an oil bath under stirring so that the innertemperature became 70° C. Then, 58.2 g (0.33 mol) of1,4-bis(dimethylsilyl)benzene was added dropwise over a period of 20minutes. After the dropwise addition was completed, the whole wasstirred at 90° C. for 3 hours. When the resulting reaction product wasanalyzed by gas chromatography, the peak derived from1,4-bis(dimethylsilyl)benzene as a starting material had disappeared.The reaction liquid was concentrated under reduced pressure underconditions of 120° C./10 hPa for 5 hours to obtain 143 g (95% yield) ofa white solid. As a result of analysis of the white solid by ¹H-NMR, itwas found that the solid was a compound represented by the followingstructure.

Table 1 and FIG. 1 show ¹H-NMR chart.

TABLE 1 ¹H-NMR Measurement δ 0.00 ppm Si—CH₃ 12H δ 0.47 to 0.52 ppmSi—CH₂—  4H δ 1.11 to 1.34 ppm Si—CH₂—CH₂—  4H δ 1.34 to 1.65 ppmSi—CH₂—CH₂—CH₂  4H δ 2.24 to 2.31 ppm Si—CH₂—CH₂—CH₂—CH  2H δ 2.68 to2.82 ppm Si—CH₂—CH₂—CH₂—CH(C═O)—CH₂  4H δ 7.20 to 7.21 ppm Si—Ph  4H(1-1)

Example 2 Synthesis of Polyimide Resin Containing Silphenylene

Into a flask fitted with a stirrer, a thermometer, and anitrogen-substituting apparatus were charged 102.5 g (0.25 mol) of2,2-bis[4-(4-aminophenoxy)phenyl]propane and 500 g of cyclohexanone.Then, 55.5 g (0.125 mol) of 4,4′-hexafluoropropylidenebisphthalicanhydride and 59.3 g (0.125 mol) of the silphenylene compound obtainedin Example 1 were added into the above flask while the temperature ofthe reaction system was regulated so as not to exceed 50° C. The wholewas further stirred at room temperature for 8 hours. Then, after areflux condenser fitted with a water-receiving device was attachedthereto, 100 g of xylene was added, the whole was heated to 150° C., andthe temperature was maintained for 6 hours, thereby a yellowish brownsolution being obtained. After the thus obtained solution was cooled toroom temperature (25° C.), it was poured into methanol to effectreprecipitation. When the resulting precipitate was dried and analyzedby NMR, a silphenylene-containing polyimide resin having the followingformulae as repeating units was obtained. FIG. 2 shows ¹H-NMR chart.

When the weight-average molecular weight (in terms of polystyrene) ofthe resin was measured by gel permeation chromatography (GPC) usingN,N-dimethylformamide as a solvent, it was found to be 25000.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the scope thereof.

1. A silphenylene compound represented by the following formula (1):

wherein R1 to R4 each independently represents a hydrogen atom or amonovalent hydrocarbon group having 1 to 6 carbon atoms, and R5 and R6each independently represents a divalent hydrocarbon group having 2 to 8carbon atoms.
 2. The silphenylene compound according to claim 1, whereinR1 to R4 each represents a methyl group.
 3. The silphenylene compoundaccording to claim 1, wherein R5 and R6 each independently represents anethylene group or an n-propylene group.
 4. A process for producing thesilphenylene compound according to claim 1, which comprises subjectingto an addition reaction a silane compound represented by the followingformula (2):

wherein R1 to R4 each independently represents a hydrogen atom or amonovalent hydrocarbon group having 1 to 6 carbon atoms, and a succinicanhydride represented by the following formula (3):

wherein R7 represents a monovalent hydrocarbon group having 2 to 8carbon atoms and containing an unsaturated group.
 5. A polyimide resinproduced by using the silphenylene compound according to claim 1 as amonomer.
 6. The polyimide resin according to claim 5, which is producedthrough a process using an addition reaction or a polycondensationreaction.